This document relates to position control of rotating turbomachine wheels.
In a rotating machine with magnetic bearings, the magnetic bearings can be controlled to control the position of the rotating assembly. In the instance of a rotating assembly that includes a turbomachine wheel, the magnetic bearings can be controlled to control the position of the turbomachine wheel relative to an adjacent, stationary turbomachine wheel shroud. The position of the turbomachine wheel relative to the shroud is affected by movement of the rotating assembly as a whole due to dynamic effects, movement of the rotating assembly as a whole and deflection of the turbomachine wheel due to pressure changes of the fluid flowing through the turbomachine wheel, and expansion/contraction of the turbomachine wheel and remaining rotating and stationary assemblies due to thermal effects. Rotating machines typically include position sensors on the rotating element, but not measuring the position of the turbomachine wheel directly. Therefore, positional changes of the turbomachine wheel that are not carried through to the location of the sensor are not accounted for.